Designation F3217 − 17 Standard Guide for Security Fasteners1 This standard is issued under the fixed designation F3217; the number immediately following the designation indicates the year of original[.]
Trang 1Designation: F3217−17
Standard Guide for
This standard is issued under the fixed designation F3217; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision A number in parentheses indicates the year of last reapproval A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1 Scope
1.1 The purpose of this guide is to provide technical
information related to understanding the features, types of
materials, and benefits of various types of security fasteners
and provide guidance in the selection and application of
security fasteners in detention and corrections facilities
1.2 Units—The values stated in inch-pound units are to be
regarded as the standard The values given in parentheses are
mathematical conversions to SI units that are provided for
information only and are not considered standard
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use It is the
responsibility of the user of this standard to establish
appro-priate safety, health and environmental practices and
deter-mine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in
accor-dance with internationally recognized principles on
standard-ization established in the Decision on Principles for the
Development of International Standards, Guides and
Recom-mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
2 Referenced Documents
2.1 ASME Standard:
ASME B1.1Unified Inch Screw Threads (UN and UNR
Thread Form)2
2.2 British Standard:
BS 1580–1Unified Screw Threads Screw Threads with
Diameters1⁄4in and Larger Requirements3
3 Terminology
3.1 Definitions:
3.1.1 bearing surface, n—area that carries load across the
face of the material
3.1.2 blind fastener, n—fastener that can be placed with
access to only one side of an application (for example, cage nuts, pop rivet®)
3.1.3 blind side, n—side of the joint that cannot be accessed
(for example, the inside surface of a tubular or box section)
3.1.4 body, n—in blind fasteners, the portion of the rivet that
expands into the parent material and in threaded fasteners, the unthreaded portion of the fastener under the head
3.1.5 bolt, n—externally threaded fastener that requires a
nut to secure the fastened joint
3.1.6 break stem, n—fastener that is installed by gripping
and pulling the end of the mandrel/stem; see Fig 1
3.1.6.1 Discussion—As installation is completed, the end of
the stem fractures at the breaker groove and is discarded, leaving the head of the stem in the fastener body
3.1.7 breaker groove, n—weakened groove in the stem or
pin of a fastener allowing breakage at a predetermined load and length; seeFig 2
3.1.8 bulbing, v—physical action of the fastener body
swell-ing (expandswell-ing radially) against the rear face of the joint when placed
3.1.8.1 Discussion—Generally found in break stem
fasten-ers and threaded inserts
3.1.9 case hardened, adv—heat-treated fastener in which the
surface is harder than the core
3.1.10 chemical-set anchor, n—anchor designed for
blind-hole installations that use a two-component structural grade catalyzing resin (usually epoxy) to bind the bolt securely in the substrate material
3.1.11 drive-pin expansion anchor, n—blind-hole expansion
anchor usually manufactured from a relatively soft alloy metal
or plastic, but can also be of steel; see Fig 3
3.1.11.1 Discussion—The anchor is expanded into the blind
hole by hammering in a supplied pin or nail into the center of the anchor
3.1.12 drive type, n—the features of a fastener head that
allows the fastener to be driven (installed or removed)
3.1.12.1 Allen head, n—hexagonal hollow socket drive
design
1 This guide is under the jurisdiction of ASTM Committee F33 on Detention and
Correctional Facilities and is the direct responsibility of Subcommittee F33.04 on
Detention Hardware.
Current edition approved Feb 1, 2017 Published August 2017 DOI: 10.1520/
F3217-17.
2 Available from American Society of Mechanical Engineers (ASME), ASME
International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
www.asme.org.
3 Available from British Standards Institution (BSI), 389 Chiswick High Rd.,
London W4 4AL, U.K., http://www.bsigroup.com.
4 See thread terminology, types of bolt and screw heads, and types of screw
points for visual reference.
Trang 2(1) Discussion—Security fastener versions have a center
pin reject feature added
3.1.12.2 Key-Rex ® , n—custom-registered
computer-designed hollow socket head design requiring a matching tool
drive to install or remove; seeFig 4.5
(1) Discussion—Generally considered a maximum security
fastener
3.1.12.3 McGard Intimidator ® , n—custom-registered
computer-designed hollow socket drive design requiring a
matching tool drive to install or remove; see Fig 5.5
(1) Discussion—Generally considered a maximum security
fastener
3.1.12.4 one-way drive, n—drive design that allows for
installation but not removal This is usually a one-way slotted head in which the slot shoulders are removed in the counter-clockwise direction
(1) Discussion—This is not considered a security fastener
with the possible exception of one-way slotted heads in which the slot shoulders are removed in the counterclockwise direc-tion
3.1.12.5 Penta Nut TM , n—tapered nut with a hollow
five-point socket that is used to tighten the nut; seeFig 6.5
3.1.12.6 Penta-plus TM , n—five-sided hollow socket security
fastener with center pin reject; see Fig 7.5
3.1.12.7 Phillips head, n—for threaded fasteners, a
tradi-tional hollow socket head design characterized by a four-lobed shape; see Fig 8
(1) Discussion—This is not considered a security fastener 3.1.12.8 Raptor TM , n—oversized head with anti-loosening
serrations on the flat bearing surface, which increases the holding power of the fastener 20 % and eliminates the need for lock washers.5
(1) Discussion—This feature can be added to Key-Rex®, Penta-plusTM, ZeroTM, or any style fastener
3.1.12.9 Robertson, n—a square hollow socket drive often
seen in woodworking fasteners
3.1.12.10 slotted head, n—for threaded fasteners, a
tradi-tional head design characterized by a cross slot in the head face; see Fig 9
5 The sole source of supply of the apparatus known to the committee at this time
is Bryce Fasteners, 1230 N Mondel Dr., Gilbert, AZ 85233 If you are aware of
alternative suppliers, please provide this information to ASTM International
Headquarters Your comments will receive careful consideration at a meeting of the
responsible technical committee, 1 which you may attend.
FIG 1 Break Stem
FIG 2 Breaker Groove
FIG 3 Drive-pin Expansion Anchor
FIG 4 Key-Rex ®
FIG 5 McGard Intimidator ®
FIG 6 Penta Nut TM
FIG 7 Penta-plus TM
FIG 8 Phillips Head
FIG 9 Slotted Head
Trang 33.1.12.11 spanner head, n—for threaded fasteners, one with
a head design characterized by horizontally opposed notches in
the head circumference or round recesses within the head face;
seeFig 10
(1) Discussion—Such designs are not especially secure and
tools for inserting or removing these types of fasteners are
easily broken They are often referred to as “snake eye”
fasteners
3.1.12.12 Torx head, n—multi-lobed hollow socket fastener
bit design as patented and licensed by Camcar Textron and the
design is characterized by a six-lobed shape with rounded
lobes.6The security version has an added center pin; seeFig
11
3.1.12.13 Torx plus head, n—multi-lobed hollow socket
fastener bit design characterized by a six-pointed shape as
patented and licensed by Camcar Textron and the design
characterized by a six-lobed shape with truncated lobes.6The
security version is a five-lobed version that has an added center
pin; see Fig 12
(1) Discussion—This design has better mechanical
proper-ties than the standard Torx but is limited in available sizes
3.1.12.14 T-REVX ® , n—multi-lobed hollow socket fastener
characterized by a seven-point shape as patented and licensed
by Bryce Fastener; seeFig 13.7
3.1.13 endurance limit/strength, n—maximum alternative
stress that a fastener can withstand for a specified number of stress cycles without failure This is not normally an issue in correctional/detention projects
3.1.13.1 Discussion—See static breaking strengths (in
pounds)
3.1.14 expansion anchor, n—anchor designed for blind-hole
installations that use a specially designed sleeve, wedge or other device that, as the fastener is tightened, the sleeve or wedge expands into the available space locking the fastener in place
3.1.15 hardening, v—changing the strength or durability
characteristics of a fastener through heat treatment or work hardening
3.1.15.1 Discussion—See case hardening, induction hardening, and through hardening.
3.1.16 head form/head style, n—characteristics of the
fas-tener head and head styles include button, pan, truss, hex, hex flange, socket head large flange, low profile, and countersunk
3.1.16.1 button head, n—for threaded fasteners, one with a
low, rounded top surface and a large, flat bearing surface; similar to a round head machine screw; seeFig 14
3.1.16.2 countersunk head, n—for threaded fasteners, one
with a level surface and a conical bearing surface; available in various nominal head angles; seeFig 15
(1) Discussion—See flat head.
3.1.16.3 fillister head—for threaded fasteners, one with a
rounded top, cylindrical sides, and flat bearing surface; seeFig
16
3.1.16.4 flat head, n—for threaded fasteners, one with a
level surface and a conical bearing surface; available in various nominal head angles; seeFig 17
(1) Discussion—See countersunk head.
6 The Torx head is covered by a patent If you are aware of an alternative(s) to
the patented item, please attach to your ballot return a description of the alternatives.
All suggestions will be considered by the committee If alternatives are identified,
the committee shall reconsider whether the patented item is necessary The
committee, in making its decision, shall follow Regulation 15.
7 The T-REVX ® is covered by a patent If you are aware of an alternative(s) to
the patented item, please attach to your ballot return a description of the alternatives.
All suggestions will be considered by the committee If alternatives are identified,
the committee shall reconsider whether the patented item is necessary The
committee, in making its decision, shall follow Regulation 15.
FIG 10 Spanner Head
FIG 11 Torx Head
FIG 12 Torx Plus Head
FIG 13 T-REVX ®
FIG 14 Button Head
FIG 15 Countersunk Head
Trang 43.1.16.5 hexagon flange head/hex flange head, n—hex head
with an integral circular collar connected to the base of the
hexagon by a conic section; see Fig 18
(1) Discussion—Normally, the flanged diameter is larger
than the width across the corners of the hexagon
3.1.16.6 hexagon head/hex head, n—for threaded fasteners,
one with a flat or indented top surface, six flat sides, and a flat
bearing surface; see Fig 19
3.1.16.7 hexagon washer head/hex washer head, n—hex
head with an integral, formed washer at the base of the
hexagon and the washer diameter may be equal to or greater
than the width across the corners; seeFig 20
3.1.16.8 oval head, n—for threaded fasteners, one with a
rounded top surface and a conical bearing surface with a head
angle of nominally 82° (90° for metric); see Fig 21
3.1.16.9 pan head, n—for threaded fasteners, one with a flat
bearing surface and a flat top surface rounding into a
cylindri-cal side surface; seeFig 22
(1) Discussion—On recessed pan heads, the top surface is
semi-elliptical, rounding into a cylindrical side surface Pan headed screws normally do not provide enough depth for the tool cavity to develop reasonable strength so it is seldom used
in security fastener designs See button head or fillister head 3.1.16.10 round head, n—one with a semi-elliptical top
surface and a flat bearing surface
(1) Discussion—This term is also used to describe a
fastener head designed without a driving surface or recess; see Fig 23
3.1.16.11 socket head, n—for threaded fasteners, one with a
flat chamfered top surface with a smooth or knurled side surface and a flat bearing surface; seeFig 24
(1) Discussion—A hexagon or spline (formerly known as
“fluted”) socket is formed in the center of the top surface
3.1.16.12 truss head, n—for threaded fasteners, one with a
rounded top surface and a flat bearing surface; the diameter of the truss head is larger in comparison to the fastener size than the diameter of the corresponding round head; see Fig 25
(1) Discussion—The design has improved mechanical
properties to Torx having higher torque and the ability to stick
to the installation tool It is more secure because only licensed installation tools can remove it Not all sizes are in stock
3.1.17 induction hardened, adj—heat-treated fastener that
has undergone a selective hardening process, using induction coils, to strengthen further a part of the fastener (usually the initial1⁄16 in (1⁄6mm) of the surface)
FIG 16 Fillister Head
FIG 17 Flat Head
FIG 18 Hexagon Flange Head/Hex Flange Head
FIG 19 Hexagon Head/Hex Head
FIG 20 Hexagon Washer Head/Hex Washer Head
FIG 21 Oval Head
FIG 22 Pan Head
FIG 23 Round Head
FIG 24 Socket Head
Trang 53.1.18 length of engagement, n—length of full-sized
fas-tener threads that engage in the nut material
3.1.18.1 Discussion—The length of the lead thread is not
counted in the length of engagement since its reduced size
minimizes any performance benefits The length of
engage-ment is usually expressed in relationship to the nominal
diameter of the screw (for example, 2 to 21⁄2 diameters of
engagement)
3.1.19 left-hand thread, n—standard thread design; winds
clockwise in a receding direction; seeFig 26
3.1.20 maximum torque, n—see ultimate torque.
3.1.21 minimum torque, n—see torque (recommended).
3.1.22 passivation/passivated, n/v—process to remove
con-taminants from the surface of stainless steel
3.1.22.1 Discussion—Also a name for the chromatic process
applied to some metallic finishes to enhance corrosion
resis-tance
3.1.23 pilot point, n—cylindrical point with a diameter
somewhat smaller than the shank diameter, which aids
align-ment and starting during installation; see Fig 27
3.1.23.1 Discussion—Also called a “dog point” (applies
normally to set screws)
3.1.24 pinned head fastener, n—hollow socket drive design
enhancement in which a central pin is introduced into the
design to render the fastener less prone to removal using
makeshift tools by eliminating adequate bearing surface in
which to exert force to the fastener; see Fig 28
3.1.24.1 Discussion—Pinned Allen, pinned Torx, and pinned
Torx Plus are examples of such designs common to the
detention and correctional industry
3.1.25 proof load, n—amount of load a fastener can
with-stand before permanent plastic deformation will occur
3.1.25.1 Discussion—See yield strength.
3.1.26 pull out, n—minimum force required to remove a
fastener axially away from the parent material
3.1.27 pulling force, n—axial force the tool applies during
the installation of rivets
3.1.28 right-hand thread, n—standard thread design; winds
counter-clockwise in a receding direction; seeFig 29
3.1.29 Rockwell Hardness Test, n—test designed to measure
the hardness of the fastener based on an alphanumeric scale
3.1.29.1 Discussion—The higher the number, the harder the
fastener Rockwell tests are used to test for decarburization and carburization and determine the amount of resistance to per-manent deformation during the testing procedure They also ensure that heat treating was performed to specification
3.1.30 screw, n—externally threaded fastener that does not
require a nut to secure the fastened joint
3.1.31 seating torque (recommended), n—recommended
value in inch-pounds or foot-pounds to which a particular threaded fastener should be tightened
3.1.32 shank, n—portion of a fastener under the head; see
Fig 30
3.1.33 shear, n—force that tends to divide an object along a
plane parallel to the opposing stresses
3.1.33.1 Discussion—Usually measured in lbf/in.2, psi, MPa, or N/m2
3.1.34 shear strength, n—resistance to transverse loading.
Maximum load that can be withstood prior to rupture when loads are applied normal to the fastener’s axis
3.1.34.1 Discussion—Usually defined as a force in Newtons
(N) or foot-pounds (lbf)
3.1.35 stem, n—part of a break stem fastener that is retained
within the body
FIG 25 Truss Head
FIG 26 Left-hand Thread
FIG 27 Pilot Point
FIG 28 Pinned Head Fastener
FIG 29 Right-hand Thread
FIG 30 Shank
Trang 63.1.35.1 Discussion—Also known as the mandrel.
3.1.36 stem retention, n—force required to separate the stem
from the body of an uninstalled break stem fastener
3.1.37 tensile strength, n—amount of longitudinal load/
elongation a fastener can withstand without failure of the
fastener or joint
3.1.37.1 Discussion—Measured in lbf/in.2, psi, MPa, or
N/m2 See ultimate tensile stress.
3.1.38 thermoset, n—polymer characterized by extreme
stiffness and undergoes a chemical change when heated Once
molded and cured “set” (hard and solid) the material cannot be
melted and re-molded
3.1.38.1 Discussion—Normally used on chemical set
an-chors
3.1.39 thread-cutting shank, n—portion of a screw of bolt
with longitudinal cut(s) in the tip of the threaded portion
intended to cut or chase threads in untapped material or clean
out threads in the nut or tapped receiver (most common use in
this guide); seeFig 31
3.1.40 thread engagement, n—amount of thread tooth that is
filled by the application material
3.1.40.1 Discussion—This measurement is usually
ex-pressed as a percentage and is used to determine optimal hole
size
3.1.41 threaded fastener, n—any screw/bolt (external
threads), nut (internal threads), or combination with machine/
standard or engineered threads and does not include custom
stamped or formed components with internal or external
threads or both
3.1.42 threaded insert, n—fastener that provides
load-bearing threads in materials too thin or brittle to accept regular
standard fasteners
3.1.43 through hardened, adv—heat-treated fastener with
uniform hardness from the surface to the core
3.1.44 torsion, n—twisting force applied to a fastener.
3.1.45 twist-off head, n—head design that incorporates a
weak shear plane whereby a torque limit is reached and the
head shears off leaving a cone or bulb rendering the fastener
non-removable; seeFig 32
3.1.46 ultimate tensile stress, n—peak longitudinal load
before rupture
3.1.46.1 Discussion—Usually measured in lbf/in.2, psi, MPa, or N/m2
3.1.47 ultimate torque, n—amount of force at which a
threaded fastener begins to strip or otherwise fail in a joint or strip the threads of an insert or nut
3.1.47.1 Discussion—For threaded inserts and clinch
fasteners, it may also be referred to as supported torque
3.1.48 Unified Coarse Thread (UNC), n—inch thread form
(60°) standard defined by ANSI/ASME
3.1.48.1 Discussion—Usually used in reference to machine
screws It is covered by ASME B1.1 and British Standard BS 1580
3.1.49 Unified Fine Threat, UNF, n—imperial thread form
standard defined by ANSI/AMSE
3.1.49.1 Discussion—Usually used in reference to machine
screws It is covered by ASME B1.1 and British Standard BS 1580
3.1.50 washer face, n—circular boss on the bearing surface
of a cap screw or nut
3.1.50.1 Discussion—The only bolt that has a washer face is
the heavy hex structural bolt; seeFig 33
3.1.51 wedge anchor, n—anchor designed for blind-hole
installations that use a specially designed wedge or spade that,
as the fastener is tightened, the wedge (usually a soft alloy) expands into the available space locking the fastener in place
3.1.51.1 Discussion—Similar to expansion anchors 3.1.52 work hardening/cold working, v—increase in metal
hardness that is the result of forming processes such as elongation, rolling, heading, and so forth
3.1.52.1 Discussion—This is particular pronounced in
steels, copper, and aluminum alloys
3.1.53 yield strength, n—measure of the resistance of
mate-rial to plastic deformation This relates to the point where a fastener will yield before it reaches a point it will not return to its original state
3.1.53.1 Discussion—When a fastener is stretched, yield
strength is the point at which the fastener will not return to its original length following testing It is measured in terms of psi
or MPa
4 Significance and Use
4.1 This guide is intended to be informative in terms of the types and uses of security fasteners in detention and corrections facilities Useful information related to products and types of fasteners, materials in which fasteners are fabricated and other technical information that will give owners, architects, and end
FIG 31 Thread-cutting Shank
FIG 32 Twist-off Head
FIG 33 Washer Face
Trang 7users adequate decision making criteria for the selection and
application of such fasteners
5 Materials
5.1 Steel:
5.1.1 Low-Carbon Steel—Low-carbon steel (C1006, C1008,
C1010) has low yield strength making it undesirable for
security fasteners and is also known as mild steel
5.1.2 Case-Hardening Steels—C1018 and C1022 are low
carbon steels used for self-threading and self-drilling screws
With a special heat-treating method called case hardening, they
can be made to have an extremely hard skin and a ductile
internal core This creates an inexpensive effective self-taping
fastener
5.1.3 Medium-Carbon 1035 Steel Having 0.35 % Carbon—
This is the steel normally used for Grade 5 bolts This steel can
be through hardened and attain 120 000- to 125 000-psi
(827.37- to 861.84-MPa) breaking strength
5.1.4 High-Carbon 1038 Steel Having 0.38 % Carbon—
This steel is normally used for Grade 8 bolts It can be through
hardened and obtain 150 000-psi (1034.21-MPa) breaking
strength
5.1.5 Alloy Steel—Alloy steels include 4037 and 8740.
These are steels with 0.37 to 0.40 % carbon alloyed with other
materials to make them tougher (represented by the call out 40
and 87) These are generally used in socket-type screws They
are more ductile than high-carbon steels They can be heat
treated to obtain 150 000 to 180 000 psi (1034.21 to 1241.05
MPa) breaking strength
5.2 Stainless Steel:
5.2.1 Austenitic Stainless Steel—Most well-known and used
in the construction industry and includes the two most
preva-lent Types 18-8 and 316 Austenitic steels make up over 70 %
of total stainless steel production
5.2.1.1 18-8—Types 305, 304, 303, 302, and 301 fall under
the 18-8 heading These all have the approximate composition
of 18 % chromium and 8 % nickel and are similarly
anticor-rosive They may also be referred to as A2 stainless After
manufacture, they usually obtain a strength of 90 000 psi
(620.52 MPa) They are stronger than mild steels but not as
hard as medium carbon steels
5.2.1.2 Type 316—Also known as 18/10 for its composition
of 18 % chromium and 10 % nickel It may also be referred to
as marine-grade stainless primarily for its increased resistance
to corrosion It is often used in cutlery and high-quality
cookware Strength is similar to 18-8 stainless steels
5.2.2 Martensitic Stainless Steel—Martensitic stainless
steels (usually called 410) are not as corrosion resistant as the
other two classes but are extremely strong and tough as well as
being highly machinable and hardenable by heat treatment
This rare form of stainless is used only for self-threading
screws and self-drilling screws
5.3 Heat-Treated Steel:
5.3.1 Case-Hardened Steel—Case hardening is a method of
heat treating 1018 and 1022 steel in a “high-carbon
atmo-sphere.” The carbon invades the skin of the fastener 0.001 to
0.005 deep making that part extremely hard, sometimes as hard
as HRC 60 The internal part is left unaffected making it
resilient to shock The result is a tough and hard fastener, especially effective in self-tapping and self-drilling screws The overall strength is not much different than a mild steel fastener This age-old process was used to improve the performance of Roman and Japanese swords
5.3.2 Through-Hardened Steel—High-carbon (1035 and
1038) and alloy steels (4037 and 8740) have enough internal carbon that, when brought to temperature, the carbon changes the structure of the whole fastener hardening it all the way through, not at just the surface This heat-treating method requires a fast quench (to retain this transformation) followed
by tempering to mitigate its brittleness and make the fastener tougher Through hardening markedly increases the overall strength of the fastener Medium-carbon steel rises from 60 000
to 120 000 psi (413.68 to 827.37 MPa), high carbon to 150 000 psi (1034.21 MPa), and alloy steels to 150 000 to 180 000 psi (1034.21 to 1241.05 MPa) Low-carbon steels (1002, 1008, and 1010) cannot be through hardened, as there is not enough internal carbon to make them transform
6 Finish
6.1 Black Phosphate—This is an historical coating
origi-nally used on socket screws and has been replaced by black oxide Both of which are poor coatings for the corrections industry as they easily rust
6.2 Dip-Spin Coatings—This is a new method of coating
steel fasteners commonly used in the auto industry It is environmentally friendly and much more anticorrosive than other platings Thickness ranges from 2 to 3 mils Since there are many brand names and formulas, it may be best specified
by its salt-spray effectiveness A 500 salt-spray resistance is easily obtained by most This is also very effective for high-carbon steel fasteners as it does not create hydrogen embrittlement It is also paintable
6.3 Hot-Dipped Galvanizing—This is a good choice for
exterior applications in larger sizes Hot-dipped galvanizing is
a rather “thick” coating and as such can be problematic on smaller sizes and fine threads This coating is usually found on fasteners used on fencing and structural steel in marine environments
6.4 Zinc Electroplating—This choice offers a mild degree of
corrosion resistance (80 to 90 salt-spray hours) but should only
be specified for indoor applications In most cases, some form
of chromate is added to increase corrosion resistance It is the industry standard for steel fasteners but has some environmen-tal problems
6.5 Tin zinc is a combination of two metals and can obtain
400 to 500 salt-spray resistance This special order plating has
a shiny color
7 Fastener Types
7.1 Non-Removable—These are fasteners that by their
de-sign are intended upon installation to have no means of removal Examples include one-way designs, blind fasteners (pop rivets), drive-pin fasteners, twist-off head fasteners, and other proprietary designs Such fasteners require the destruc-tion of the head with a saw, grinder, or torch to remove the item
Trang 8fastened These types are excellent for items that need to be
secured and left alone Examples include:
7.1.1 Toilet partitions,
7.1.2 Detention furnishings,
7.1.3 Detention accessories,
7.1.4 Detention hollow metal to nonmetallic substrates
where welding is not an option, and
7.1.5 Door trim hardware (weather stripping and
thresh-olds)
7.2 Removable—These are fasteners that by their design are
intended to be installed and removed using special tools For
security fasteners, this includes spanner head, pinned head
Allen, pinned head Torx, pinned head Torx-Plus, McGard, and
others In these locations, regular access for maintenance or
potential access for replacement necessitates the application of
removable fasteners In security applications, a reasonably
secure head design is required to make removal by
non-authorized individuals extremely difficult Examples include:
7.2.1 Detention hardware;
7.2.2 Detention glazing stops;
7.2.3 Some elements of detention ceilings;
7.2.4 Detention light fixtures; and
7.2.5 Furniture, fixtures, and equipment requiring regular
maintenance
8 Head Design
8.1 Head design is normally selected for the intended
individual use and by the need to be flush with the adjacent
surface or not The overall shape of the head is not specifically
related to the security level of the fastener with the exception
of nonremovable types The other facet of head design is the
design of the tool required to remove the fastener in the case of
removable types
8.1.1 Non-removable Security Fastener Head Options for
Considerations—The selection of the right fastener depends on
several issues including the size of the fastener, spacing, level
of security, required load-carrying capacity, and corrosion
resistance
8.1.1.1 Low-security/low-strength uses in metal substrates
normally require the use of blind fasteners (pop rivets)
Aluminum can be used for low-strength applications and
stainless steel for higher strength applications One-way screws
can also be allowed but only where acceptable to the
institu-tion
8.1.1.2 Moderate-security/moderate-strength uses in
con-crete and masonry substrates often involve the use of drive-pin
fasteners (Zamac) or proprietary deformed shank fasteners
(Rawl Spikes)
8.1.1.3 High-security/high-strength uses in concrete and
masonry substrates normally indicate the use of bolts or nuts
with twist-off heads The bolts may be chemically set anchors,
expansion anchors, or even embedded anchors For
post-applied applications, chemically set anchors are preferred
unless the application will be compromised with the
applica-tion of high heat as in a fire since thermoset polymers can
soften on application of heat in the area of a few hundred
degrees Fahrenheit Follow manufacturer’s recommendations
for use of such products
8.1.2 Removable Security Fastener Head Options for Consideration—The selection of the right fastener also
de-pends on similar factors including the size of the fastener, spacing, level of security, required load-carrying capacity, and corrosion resistance It is very advantageous to select a fastener tooling solution that requires maintenance personnel to have to carry the least sizes and types of tools
8.1.2.1 Low-security uses include spanner head designs However, the utility of such uses may be impractical because
of the additional tools required to affect maintenance 8.1.2.2 Medium-security uses are generally the domain of pinned Torx, pinned hex, or pinned Torx-Plus designs This fastener type dominates the detention and corrections industry today because they are widely recognized, available, and the cost per unit is reasonable However, with the tool bits becoming generally available through hardware and home improvement stores, the relative security is somewhat reduced
As a result, institutions shall be more diligent in controlling contraband including such tool bits
8.1.2.3 High-security uses would include Penta-Plus, Zero, and Penta Nut designs These fasteners have keys controlled and monitored by the manufacturer They are also designed to
be more difficult to remove by self-made tools The cost per unit is higher
8.1.2.4 Maximum security can be obtained through the use
of custom registered computer-designed hollow socket head design such as McGard Intimidator or Bryce Key-Rex Such fasteners are more costly and difficult to obtain making their use limited in the market, but because the head design is registered to the user, no one but the user can purchase tool bits making them more secure Because they are more difficult to obtain, purchasing and maintenance of spare fasteners is advised
9 Corrosion Resistance
9.1 Depending on whether the fasteners are intended for exterior use, interior dry locations, or interior wet locations, corrosion resistance is a concern Galvanic corrosion between dissimilar materials can also be a problem even when fasteners are used in formally dry conditions Special care in selection shall be taken in areas where extreme environments are expected such as salt air environments, as well as kitchens and laundries where fatty acids and harsh cleaning chemicals are used
9.1.1 Unplated carbon steels exhibit excellent strength and durability but are not good values where corrosion or humidity
is a concern Such fasteners are normally treated with a phosphate or black oxide coating, but this only adds minor corrosion resistance Field painting may be added for extra protection However, care shall be taken for removable fasten-ers that the removal tool cavity is not filled with paint rendering the fastener difficult or impossible to use
9.1.2 Plated carbon steels provide similar strength and durability with increased corrosion resistance and are generally adequate for low-humidity indoor applications The plating can
be worn off in the thread contact area so, for areas where corrosion may be a concern, use of a thread-treating compound
is recommended
Trang 99.1.3 Dip spin fasteners with 500 salt spray hour finishes are
the optimum choice for high-humidity indoor and outdoor
applications Unfortunately, most steel security fasteners are
not stocked with this coating and may require a special order
plating fee
9.1.4 Hot-dipped galvanized carbon steels are acceptable
for larger bolt sizes, but the relative thickness of such coatings
make this coating unworkable for smaller bolt sizes, especially
those with finer pitch threads
9.1.5 Stainless steels provide excellent corrosion resistance
but, depending on the type of stainless steel used, care shall be
taken not to over torque these fasteners as they can often gall
or break Use of anti-gall or thread-locking compounds as well
as careful torqueing procedures can yield excellent results
Type 18-8 stainless steel is more prone to this kind of problem
than 316 stainless steels, but Type 18-8 is more common in use
in the construction industry Stainless steel fasteners are
normally more costly than their carbon steel counterparts,
plated or not
9.1.6 Per the galvanic chart included as an Appendix X4,
fasteners should also be selected relative to the substrates in
which they are installed for metal-to-metal contact Materials
for fasteners should be as close together as possible on the
chart to avoid corrosion caused by galvanic action Failure to
do so may result in fasteners that may fail or become corroded
together and ultimately irremovable
10 Best Practices
10.1 Use of Fine Versus Coarse Threads—In most cases,
course threads are better than fine threads though this changes
depending on the fastener size, material, and finish The factors
noted in 10.1.1 and 10.1.2 should be considered when
selecting/specifying security fasteners
10.1.1 In general, coarse threads are more durable and have
a greater resistance to cross threading and stripping They are
less prone to damage and do not have to be “handled with
care.” They install faster They are not as prone to plating
buildup and, therefore, a good choice for hot-dipped
galvaniz-ing and other “thick” platgalvaniz-ing methods Course threads are also
less susceptible to thread galling because of more rotations
required to tighten a fine thread and, as such, may be a better
choice for stainless steel fasteners
10.1.2 However, fine threads are reported to be stronger
than the corresponding coarse threaded bolts or screws Fine
threads also have fewer tendencies to loosen under vibration so
use in dynamic use applications is important Finer threads can
also be more easily trapped into difficult-to-tap materials and
thin-walled sections such as hollow metal Fine threads require
less tightening torque to develop equivalent preloads to the
corresponding coarse thread bolt sizes; an important issue is to
avoid bolt breakage during installation Over tightening is a
concern as fine threads tend to strip their threads easily
10.2 Use of Thread-Cutting Screws—In certain conditions,
the use of thread-cutting screws is a good practice This is
especially true for removable window stops During
construction, when the stops can be removed, the pre-drilled,
pre-tapped holes can be filled with dirt or paint The
thread-cutting shanks on the screws can clean the receiving threads clean of foreign matter, though care shall be taken not to cross thread the hole
10.3 Use of Thread Compounds—Use of thread compounds
is highly recommended These can be pre-applied at the factory
or individually as the fastener is being installed
10.3.1 If there are a large number of the exact sized fasteners to be used, factory applied compounds are more cost effective In areas where the compound is used to resist galling
or corrosion, this practice can yield excellent results in terms of cross threading, stuck fasteners, and even broken fasteners 10.3.2 When thread-locking compounds are specified, they can enhance not only corrosion resistance, but also security Depending on the type of thread-locking compound used, some fasteners can only be removed when subjected to heat from a heat gun or iron
10.3.2.1 Care should be taken though when used in con-junction with laminated glass or polycarbonate glazing appli-cations because the heat required to soften the thread locker may damage the polymer components of such glazing 10.3.2.2 Examples of factory applied thread locking com-pounds include Nylock and ND industries
10.3.2.3 These methods can be added to existing fasteners inexpensively but require a $200.00 minimum They are more cost effective for installation than Loc Tite, as long as you have over 2000 pieces
10.3.2.4 There are three different types of these factory applied thread lockers:
(1) “Patch lock” that is a two-part epoxy that is unmixed
until it is threaded in,
(2) Nylon pellet drilled in the side, and (3) Nylon strip slit into the side.
10.3.2.5 Examples of a field-applied thread locker include Loc Tite and other brands This is normally a single-component fluid applied to the threads immediately before installation These come in different strengths
10.4 Use of Good Torqueing Procedures—This is an area
often neglected Though security fasteners cannot be a 100 % deterrent, improperly tightened fasteners can be easily re-moved sometimes even with fingers only All security screws should be torqued to manufacturer’s recommended minimum values During construction, it is a good practice for the construction manager to randomly test fasteners to check on the subcontractor’s diligence in meeting specified fastener tightness If nonconforming installations are found, then the subcontractor should be required to tighten all screws under direct observation of an authorized inspector
10.5 Removing and Replacing Broken Fasteners—Often
during removing and replacing screws, a screw may shear off particularly when the mating pocket is filled with foreign matter In such cases, the fastener remnants should be removed, and the mating pocket re-drilled and re-tapped As most fastener spacing is based on good engineering practice, merely leaving a screw out can result in inadequate performance of the assembly, thereby reducing security Diligence in identifying broken fasteners and repairing them will result in maintenance
of required design criteria and anticipated performance
Trang 1011 Application Guidelines
11.1 Overview—Detention and corrections facilities are
complex built environments with many products, assemblies,
and systems integrated into the whole The huge diversity of
materials that need to be connected together to form a secure
setting means there are as many potential fastening methods
and materials which need to be considered in a facility design
These range from fasteners which are fixed once installed and
require no disassembly or maintenance to those which must be
removed and replaced on a regular basis for regular
mainte-nance or repair The location and use condition of the fastener
also are important considerations Owners, architects,
contrac-tors and material suppliers all play a role in the selection and
use of such fasteners With good information on which to base
the selection, the performance of the fastener can be reasonably
anticipated and at the expected level of security
11.2 Non-removable Fasteners—There are many locations
within a detention and corrections facility where the fastener
can be installed and forgotten about Once installed, any
removal can be done through destructive means such as
grinding or torching off the fastener head There are many
choices of this type that can be used for everything from light
duty fasteners which may secure small parts to large
compo-nents requiring significant structural loading
11.2.1 Small, Light Duty Fasteners—These would include
blind hole fasteners (commonly referred to as pop-rivets),
small screws with heads designed to allow tightening but not
removal, to small drive pin fasteners The material and loading
capacity of such fasteners should be reviewed, but normally the
locations where such devices might be used are low security,
and the risk of removal is minimal This type of use is generally
for statically loaded connections (not where vibration or
expansion and contraction might loosen the connection)
Where the item being removed might be used for some other
more dangerous or destructive purpose, more secure selections
might be considered
11.2.1.1 Examples of this type of use:
(1) Non-removable door hardware (thresholds and
weath-erstripping)
(2) Toilet partitions.
(3) Brackets and Accessories—Marker boards and tack
boards, projection screens, hollow metal trims, and similar
items
11.2.1.2 Types of fasteners used:
(1) Blind hold fasteners of aluminum or stainless steel.
(2) One-way slotted head machine bolts and nuts, or
self-drilling sheet metal screws of plated steel or stainless steel
(3) Plastic or metallic drive pin fasteners Use of plastic
should be minimized due to relative ease of defeating such
fasteners by mechanical force or application of heat
(4) Deformed shank nail-ins (Rawl Spikes).
11.2.2 Medium Duty Fasteners—These might be used for
items which are larger or have moderate loading criteria
including slight dynamically loaded conditions (low degree of
vibration or expansion and contraction of the items being
fastened) This can also include items that have a higher degree
of security associated with them
11.2.2.1 Examples of this type of use:
(1) Hollow metal connections of substrates where blind
connections are not possible
(2) Small equipment mountings.
(3) Small furnishings and accessories mountings in
unsu-pervised areas
11.2.2.2 Types of fasteners used:
(1) Metallic drive pin fasteners of larger diameter greater
than1⁄4in in diameter
(2) Deformed shank nail-ins (Rawl Spikes) greater than1⁄4
in in diameter
(3) Twist-off head machine screws, bolts, or nuts of
mod-erate diameter (less than1⁄2in in diameter)
11.2.3 Heavy Duty Fasteners—For use on items which are
larger or have high loading criteria including dynamically loaded conditions (high degree of vibration or expansion and contraction of the items being fastened) This also includes items that have a higher degree of security associated with them
11.2.3.1 Examples of this type of use:
(1) Detention furnishings.
(2) Large equipment in inmate areas.
(3) Exposed securements at hollow metal doors and frames
or other locations on the secure perimeter
11.2.3.2 Types of fasteners used:
(1) Twist-off head machine screws, bolts, or nuts of large
diameter (1⁄2in diameter or greater)
11.3 Removable Fasteners—Many of the fasteners in a
D&C facility must be accessed on a regular basis The use of such fasteners must deny access to detainees/inmates but allow for maintenance or service personnel when necessary Such fasteners are usually of one or two types in order to keep numbers and types of maintenance tools to a minimum It is not uncommon for these fasteners to be as small as a #6 machine screw to as large as3⁄4in in diameter through the vast majority
of such screws are in the #12 to1⁄4in diameter range
11.3.1 Drive Design—In most modern facilities across the
country and even the world, the most common product has been the hollow socket Torx head design with the center pin reject also known as “pinned Torx.” This design provides a good level of security as well as serviceability in terms of being able to be installed and removed multiple times with limited reduction in security or degradation of the tool head recesses The Torx head has been out on the marketplace for decades The pinned Torx design was fairly rare on the open market, but currently the tool bits can be obtained from local home and hardware stores They are normally offered as inserts to drive tools and are relatively inexpensive There are other products that have come out in the marketplace including the Torx Plus truncated 6 lobed design Like original 6 lobed Torx design originally designed for the automotive industry and military, this head design has certain benefits, but the sizes available in the Torx Plus make it a questionable choice for a single tool head platform Similarly, the pinned Torx Plus tools are not as readily available as the standard pinned Torx tools mostly because of their limited use in the public marketplace Use of other head designs such as “Pinned Allen,” Spanner Head or other type is not recommended if based on nothing else but the